WHY DID THE UK PAY £500 MILLION TO SWITCH OFF WIND TURBINES LAST YEAR? GREEN HYDROGEN CAN SOLVE THIS PROBLEM

The UK Government is proud of the UK’s position as the world-leader in offshore wind turbines - the UK generated 25% of its electricity from this zero-carbon source last year. However, there is an inconvenient truth behind this major achievement.

The government mandates the National Grid to use the electricity generated by the wind turbines, but the Grid cannot always handle the power they generate. In those cases, the wind turbines have to be deactivated, but the government (i.e. you, the tax-payer) still has to stump up large amounts cash for, literally, nothing.

The technical name for this process is “curtailment” – another word is waste - and the Government paid £299m for curtailment in 2020, and £507m in 2021 (check out the figures here). As we build more turbines - Scotland is planning to double its production of renewable energy - those figures will keep rising.

The reasons for curtailment are two-fold: Over 40% of all wind-turbine electricity in the UK comes from Scotland, but the transmission network was not designed for huge energy flows between Scotland and England. As a result, operators in Scotland are frequently required to switch off their wind turbines, while English gas-fired power stations are being paid to increase output. More transmission cables from north to south would solve this problem, but electricity pylons are even less popular than onshore wind turbines. 

The second issue with renewables is their intermittency. Not every day is windy – not even in the North Sea. So, the second issue to solve is storage of the large amounts of electricity that are available when there is insufficient Grid demand, and we are not talking about a 100KWH Tesla battery packs, we are talking about megawatts. The solution is ‘green’ hydrogen.

Rather than switching off wind turbines when their electricity is not usable, the turbines should be used to generate electricity to electrolyse water into zero-emission ‘green’ hydrogen. This becomes stored electricity, available to use at a later date in a fuel cell to generate electricity on demand, to power a car, a truck, an aeroplane, or to send electricity back to the Grid in periods of peak demand.

The battery lobby say this is neither efficient nor affordable, but are they correct? Certainly, energy will be lost in the transition from renewable energy to hydrogen and back again. An MIT analysis indicates that hydrogen made from electrolysis is 75% efficient; long-term storage/transportation of the hydrogen is 90% efficient; and a fuel cell turning hydrogen back into electricity is 60% efficient – so, the “round-trip” efficiency (the net amount of usable energy) is 40%.

That may not sound great until you put it into context. For example, a coal-fired power station is 33% efficient, and a solar panel is 20% efficient. In other words, efficiency is relative to the raw material you are using. The fact that 80% of the light falling on current solar panels is “wasted” is meaningless – sunlight and wind are available to us in infinite abundance, and, the IEA, has confirmed that “solar PV is now the cheapest source of electricity in history.” So, in this context, turning wind into electricity at a 40% efficiency clearly makes sense – and yes, battery storage would theoretically deliver greater efficiency, but at the scale required, simply not feasible or sustainable.

And the cost? Well, the turbines already exist, so there is almost no marginal cost in producing the electricity, and with growing demand, the cost of the electrolysers is coming down all the time, very much as wind turbines have done over the last 15 years.